During aerial refueling, a boom may be extended from a tanker aircraft. An aircraft to be refueled may position itself relative to the tanker aircraft and, more particularly, relative to the refueling boom. A connection is established between the refueling boom and the aircraft to be refueled such that fuel may be dispensed from the tanker aircraft to the aircraft to be refueled so as to effectuate the refueling operation. Following refueling, the refueling boom may be disconnected from the aircraft that was to be refueled.
The refueling boom may be retractable. As such, the boom may be extended from the tanker aircraft prior to a refueling operation and may be retracted so as to be stowed under the tanker aircraft following the refueling operation. In this regard, the refueling boom may include a plurality of tubes at least partially nested within one another so as to facilitate the extension or telescoping of the tubes in order to extend the refueling boom and the retraction of the tubes within one another in order to facilitate the retraction of the refueling boom. The extension and retraction of the refueling boom may be actuated in various manners including hydraulically and electrically. For example, an aerial refueling boom system may include a hydraulic system including a hydraulic pressure source configured to cause the refueling boom to controllably extend prior to refueling operations and to controllably retract following refueling operations. In addition, the hydraulic system may maintain the refueling boom in the retracted position when not in use.
The hydraulic system may also include a number of valves, regulators and the like for appropriately directing and applying the hydraulic pressure. For example, the hydraulic system may include a relief valve, a boom telescoping control valve and extend/retract flow control regulators. In an instance in which there is a hydraulic system anomaly, such as attributable to the hydraulic fluid or some components of the hydraulic system malfunctioning, such as a malfunction of the relief valve, the boom telescoping control valve and/or the extend/retract flow control regulators, the refueling boom may extend in an anomalous fashion. As it is desirable to control the position and operation of the refueling boom under all circumstances, such anomalous boom extensions may be disadvantageous.